*2.2. Outcomes*

The primary outcome was to evaluate a possible modification of the microbiota at six months of therapy. The secondary outcomes were to evaluate: (1) the possible association of the microbiome characteristics with C-reactive protein (CRP) levels at six months of therapy; (2) the possible predictive role of the microbiome on the response to anti-TNF therapy. Response to adalimumab therapy was defined as a decrease in the Harvey-Bradshaw index (HBI) score greater than or equal to 2 (or HBI ≤ 4 at six months), in the absence of corticosteroid therapy and with adalimumab still in therapy, in agreemen<sup>t</sup> with the literature [12]. The study followed the principles of the Declaration of Helsinki and was approved by the local ethical committee (Comitato Etico Interaziendale A.O.U. Città della Salute e della Scienza di Torino-A.O. Ordine Mauriziano-A.S.L. Città di Torino) (approval code 0056924).
